Malakoplakia of the Genitourinary Tract: A Report of 3 Cases

ABSTRACT

Malakoplakia is a rare chronic inflammatory disease, most commonly found in the urinary tract. It has been associated with chronic infections, malignancies, and immunocompromised states. The authors present 3 cases of malakoplakia of the genitourinary tract, seen in 3 female patients who sought medical attention due to pain or bleeding. The histopathological examination in all cases was compatible with malakoplakia and characterized by the presence of Michaelis-Gutmann bodies. All patients were effectively treated with surgical excision in combination with antibiotic therapy.

Malakoplakia was first introduced in 1902 by Michaelis and Gutmann [1,2]. It is a rare inflammatory condition that is usually found in the urinary tract, mainly in the urinary bladder [3,4]. It forms soft yellow plaques, hence its name from the Greek words malako (soft) and plakia (plaque). It is caused mainly by chronic bacterial infections (especially Escherichia coli) and rarely by viral or parasitic infections [5]. It has also been associated with tumors and immunosuppressed states [10-13]. The 3 cases reported in this document had a more unusual form of malakoplakia of the genitourinary tract.

CASE REPORTS

Case 1

A 68-year-old female presented with the complaint of occasional vaginal bleeding for 1 month. The gynecological examination revealed the presence of a white, fleshy, exophytic mass (about 2 cm in diameter) occupying the external urethral meatus. The rest of the physical examination and the transvaginal ultrasound examination were normal. The lesion was painless and fragile, bleeding easily on manipulation. It did not cause any voiding dysfunction.

The differential diagnosis included urethral caruncle and urethral carcinoma. Urine analysis was normal. Her blood glucose was 122 mg/dL. The patient had a past medical history of diabetes mellitus, hypertension, rheumatoid arthritis, and osteoporosis. She was taking insulin, teriparatide, low-dose prednisone, and valsartan.

The mass was removed surgically under general anesthesia, using an electrocautery blade electrode for cutting and fulguration. Hemostasis was adequate and no sutures were needed. An 18 Fr Foley catheter was placed for 24 hours. Antibiotic treatment and analgesia were included in the treatment regimen. After the Foley catheter was removed, the patient was discharged with trimethoprim/sulfamethoxazole for 4 days.

The histopathological examination revealed the presence of abundant histiocytes with slightly eosinophilic granular cytoplasm, rare neutrophils and lymphocytes, and many intracellular and extracellular basophilic inclusions, which are a feature of Michaelis- Gutmann bodies (Figure 1). The inclusions stained positive with the periodic acid-Schiff (PAS) reagent and alcian blue (Figure 2). These features are pathognomonic of malakoplakia.

Follow-up after 2 years showed no recurrence. The authors suspect that the use of steroids and history of diabetes mellitus may have played a role in the pathogenesis of malakoplakia in this case.

Case 2

A 56-year-old African-American female presented with severe pain and difficulty sitting for several months. She also stated that urination was extremely difficult. She described a decreased urine stream and blood in the urine, which was also cloudy and smelly. She stated â€œsomething is hanging out and it hurts to do anythingâ€ and the condition seemed to be getting worse. In addition, the patient complained of constantly leaking urine and burning and pain with urination that she thought was due to a possible infection.

On gynecological examination, a 3 cm anterior vaginal mass was found that was protruding from the introitus and was excruciatingly painful to any touch. The entire vagina was obstructed, and hard calcified material could be palpated from the outside. Magnetic resonance imaging done at the time of diagnosis revealed a 2.3 cm diameter diverticulum posterior to the urethra that contained 3 stones.

The differential diagnosis included urethral diverticulum and urethral carcinoma. Urine analysis revealed a severe urinary tract infection. Past medical history was significant for hypertension, for which she was on atenolol.

A Foley catheter was placed immediately and antibiotics were started to treat the infection. Four weeks later, the mass was excised surgically under general anesthesia and the diverticular defect was repaired using a biological graft (Figure 3; Figure 4; Figure 5). Foley drainage was maintained for another 2 weeks. Antibiotics and analgesia were continued for 6 weeks after the procedure. She remained continent and was completely cured of the pain and infection.

Histopathological examination revealed the presence of abundant histiocytes with slightly eosinophilic granular cytoplasm, rare neutrophils and lymphocytes, and many intracellular and extracellular basophilic inclusions that stained positive with the PAS reagent and alcian blue. Again, these features are pathognomonic of malakoplakia.

The patient later reported a history of passing kidney stones 12 years prior to this presentation. Chronic inflammation in the urethra may have led to malakoplakia in her case.

Case 3

A 26-year-old, 34-week pregnant female patient (gravida 1, para 0) presented with complaints of occasional vaginal bleeding, a mass, and burning on urination for the past 3 months. A pink, irregular, exophytic mass (about 2 cm in diameter) arising from the external urethral meatus was noted on gynecological examination. The rest of the physical examination and the transvaginal ultrasound examination were normal. The lesion was slightly painful, bled easily on touch, and caused burning with urination according to the patient.

The differential diagnosis included a urethral caruncle or urethral carcinoma. Urine analysis was normal. The patient was otherwise very healthy. The mass was removed surgically under general anesthesia, hemostasis was assured, and no sutures were placed. Foley drainage was used for 48 hours, along with antibiotics and analgesia for the next 5 days. Antibiotic prophylaxis was used for the duration of the pregnancy.

Histology again revealed the classic features of malakoplakia. The patient recovered without event and went on to have a successful vaginal delivery and no recurrence. Pregnancy may have caused an immunocompromised state, leading to this case of malakoplakia.

DISCUSSION

Malakoplakia is a chronic inflammatory condition characterized by the accumulation of phagocytes. Its most common location is the urinary tract, including the urinary bladder, ureters, prostate, and kidneys [6]. Malakoplakia of the urethra is an extremely rare entity and very few cases have been reported [7]. Malakoplakia has also been found in the gastrointestinal tract, lungs, skin, vagina, and brain [8-10]. It is more commonly found in immunosuppressed patients, such as those who have undergone transplantation or those who have AIDS [11]. It occasionally coexists with malignant tumors, such as colon adenocarcinoma or prostatic adenocarcinoma [12,13].

The pathophysiology of malakoplakia is unclear, but it is believed to be caused by inadequate bacterial phagocytosis due to lysosomal dysfunction. This results in the accumulation of bacteria and an increased concentration of calcium and iron in the macrophages, which leads to the formation of the characteristic Michaelis- Gutmann bodies [14].

Malakoplakia is a benign, usually self-limiting disease. It can mimic malignancy macroscopically and clinically [15]. The diagnosis is confirmed by biopsy and histopathological examination. Treatment modalities include surgical excision and long-term antibiotic treatment (eg, quinolones and trimethoprim/sulfamethoxazole) in order to provide coverage against E. coli [16].

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